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Qi F, Zhang P. High-resolution multi-spectral snapshot 3D imaging with a SPAD array camera. OPTICS EXPRESS 2023; 31:30118-30129. [PMID: 37710561 DOI: 10.1364/oe.492581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 08/14/2023] [Indexed: 09/16/2023]
Abstract
Currently, mainstream light detection and ranging (LiDAR) systems usually involve a mechanical scanner component, which enables large-scale, high-resolution and multi-spectral imaging, but is difficult to assemble and has a larger system size. Furthermore, the mechanical wear on the moving parts of the scanner reduces its usage lifetime. Here, we propose a high-resolution scan-less multi-spectral three-dimensional (3D) imaging system, which improves the resolution with a four-times increase in the pixel number and can achieve multi-spectral imaging in a single snapshot. This system utilizes a specially designed multiple field-of-view (multi-FOV) system to separate four-wavelength echoes carrying depth and spectral reflectance information with predetermined temporal intervals, such that one single pixel of the SPAD array can sample four adjacent positions through the four channels' FOVs with subpixel offset. The positions and reflectivity are thus mapped to wavelengths in different time-bins. Our results show that the system can achieve high-resolution multi-spectral 3D imaging in a single exposure without scanning component. This scheme is the first to realize scan-less single-exposure high-resolution and multi-spectral imaging with a SPAD array sensor.
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Taher J, Hakala T, Jaakkola A, Hyyti H, Kukko A, Manninen P, Maanpää J, Hyyppä J. Feasibility of Hyperspectral Single Photon Lidar for Robust Autonomous Vehicle Perception. SENSORS (BASEL, SWITZERLAND) 2022; 22:5759. [PMID: 35957316 PMCID: PMC9371088 DOI: 10.3390/s22155759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/26/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
Autonomous vehicle perception systems typically rely on single-wavelength lidar sensors to obtain three-dimensional information about the road environment. In contrast to cameras, lidars are unaffected by challenging illumination conditions, such as low light during night-time and various bidirectional effects changing the return reflectance. However, as many commercial lidars operate on a monochromatic basis, the ability to distinguish objects based on material spectral properties is limited. In this work, we describe the prototype hardware for a hyperspectral single photon lidar and demonstrate the feasibility of its use in an autonomous-driving-related object classification task. We also introduce a simple statistical model for estimating the reflectance measurement accuracy of single photon sensitive lidar devices. The single photon receiver frame was used to receive 30 12.3 nm spectral channels in the spectral band 1200-1570 nm, with a maximum channel-wise intensity of 32 photons. A varying number of frames were used to accumulate the signal photon count. Multiple objects covering 10 different categories of road environment, such as car, dry asphalt, gravel road, snowy asphalt, wet asphalt, wall, granite, grass, moss, and spruce tree, were included in the experiments. We test the influence of the number of spectral channels and the number of frames on the classification accuracy with random forest classifier and find that the spectral information increases the classification accuracy in the high-photon flux regime from 50% to 94% with 2 channels and 30 channels, respectively. In the low-photon flux regime, the classification accuracy increases from 30% to 38% with 2 channels and 6 channels, respectively. Additionally, we visualize the data with the t-SNE algorithm and show that the photon shot noise in the single photon sensitive hyperspectral data contributes the most to the separability of material specific spectral signatures. The results of this study provide support for the use of hyperspectral single photon lidar data on more advanced object detection and classification methods, and motivates the development of advanced single photon sensitive hyperspectral lidar devices for use in autonomous vehicles and in robotics.
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Affiliation(s)
- Josef Taher
- Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute FGI, National Land Survey of Finland, 02150 Espoo, Finland; (T.H.); (A.J.); (H.H.); (A.K.); (P.M.); (J.M.); (J.H.)
- Department of Computer Science, Aalto University School of Science, 02150 Espoo, Finland
| | - Teemu Hakala
- Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute FGI, National Land Survey of Finland, 02150 Espoo, Finland; (T.H.); (A.J.); (H.H.); (A.K.); (P.M.); (J.M.); (J.H.)
| | - Anttoni Jaakkola
- Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute FGI, National Land Survey of Finland, 02150 Espoo, Finland; (T.H.); (A.J.); (H.H.); (A.K.); (P.M.); (J.M.); (J.H.)
| | - Heikki Hyyti
- Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute FGI, National Land Survey of Finland, 02150 Espoo, Finland; (T.H.); (A.J.); (H.H.); (A.K.); (P.M.); (J.M.); (J.H.)
| | - Antero Kukko
- Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute FGI, National Land Survey of Finland, 02150 Espoo, Finland; (T.H.); (A.J.); (H.H.); (A.K.); (P.M.); (J.M.); (J.H.)
| | - Petri Manninen
- Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute FGI, National Land Survey of Finland, 02150 Espoo, Finland; (T.H.); (A.J.); (H.H.); (A.K.); (P.M.); (J.M.); (J.H.)
| | - Jyri Maanpää
- Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute FGI, National Land Survey of Finland, 02150 Espoo, Finland; (T.H.); (A.J.); (H.H.); (A.K.); (P.M.); (J.M.); (J.H.)
- Department of Computer Science, Aalto University School of Science, 02150 Espoo, Finland
| | - Juha Hyyppä
- Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute FGI, National Land Survey of Finland, 02150 Espoo, Finland; (T.H.); (A.J.); (H.H.); (A.K.); (P.M.); (J.M.); (J.H.)
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Choudhury D, McNicholl DK, Repetti A, Gris-Sánchez I, Li S, Phillips DB, Whyte G, Birks TA, Wiaux Y, Thomson RR. Computational optical imaging with a photonic lantern. Nat Commun 2020; 11:5217. [PMID: 33060608 PMCID: PMC7562926 DOI: 10.1038/s41467-020-18818-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 09/10/2020] [Indexed: 11/24/2022] Open
Abstract
The thin and flexible nature of optical fibres often makes them the ideal technology to view biological processes in-vivo, but current microendoscopic approaches are limited in spatial resolution. Here, we demonstrate a route to high resolution microendoscopy using a multicore fibre (MCF) with an adiabatic multimode-to-single-mode “photonic lantern” transition formed at the distal end by tapering. We show that distinct multimode patterns of light can be projected from the output of the lantern by individually exciting the single-mode MCF cores, and that these patterns are highly stable to fibre movement. This capability is then exploited to demonstrate a form of single-pixel imaging, where a single pixel detector is used to detect the fraction of light transmitted through the object for each multimode pattern. A custom computational imaging algorithm we call SARA-COIL is used to reconstruct the object using only the pre-measured multimode patterns themselves and the detector signals. Here, the authors demonstrate a route to high resolution microendoscopy using a multicore fibre with a photonic lantern. They show that distinct multimode patterns of light can be projected from the output of the lantern by individually exciting the single-mode MCF cores, whose patterns are highly stable to fibre movement.
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Affiliation(s)
- Debaditya Choudhury
- Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.,EPSRC IRC Hub, MRC Centre for Inflammation Research, Queen's Medical Research Institute (QMRI), University of Edinburgh, Edinburgh, UK
| | - Duncan K McNicholl
- Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.,EPSRC IRC Hub, MRC Centre for Inflammation Research, Queen's Medical Research Institute (QMRI), University of Edinburgh, Edinburgh, UK
| | - Audrey Repetti
- Institute of Sensors, Signals and System, Heriot-Watt University, Edinburgh, EH14 4AS, UK.,Department of Actuarial Mathematics and Statistics, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Itandehui Gris-Sánchez
- Department of Physics, University of Bath, Claverton Down, Bath, BA2 7AY, UK.,ITEAM Research Institute, Universitat Politècnica de València, 46022, Valencia, Spain
| | - Shuhui Li
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 430074, Wuhan, Hubei, China.,School of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, UK
| | - David B Phillips
- School of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, UK
| | - Graeme Whyte
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Tim A Birks
- Department of Physics, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Yves Wiaux
- Institute of Sensors, Signals and System, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Robert R Thomson
- Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK. .,EPSRC IRC Hub, MRC Centre for Inflammation Research, Queen's Medical Research Institute (QMRI), University of Edinburgh, Edinburgh, UK.
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4
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Xiang X, Dong R, Quan R, Jin Y, Yang Y, Li M, Liu T, Zhang S. Hybrid frequency-time spectrograph for the spectral measurement of the two-photon state. OPTICS LETTERS 2020; 45:2993-2996. [PMID: 32479441 DOI: 10.1364/ol.392744] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 04/26/2020] [Indexed: 06/11/2023]
Abstract
In this Letter, a hybrid frequency-time spectrograph combining a tunable optical filter and a dispersive element is presented for measurement of the spectral properties of the two-photon state. In comparison with the previous single-photon spectrograph utilizing the dispersive Fourier transformation (DFT) technique, this method is advanced since it avoids the need for additional wavelength calibration and the electronic laser trigger for coincidence measurement; therefore, its application is extended to continuous wave (CW) pumped two-photon sources. The achievable precision of the spectrum measurement has also been discussed in theory and demonstrated experimentally with a CW pumped periodically poled lithium niobate (PPLN) waveguide-based spontaneous parametric down-conversion photon source. Such a device is expected to be a versatile tool for the characterization of the frequency entangled two-photon state.
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Milián C, Kartashov YV, Torner L. Robust Ultrashort Light Bullets in Strongly Twisted Waveguide Arrays. PHYSICAL REVIEW LETTERS 2019; 123:133902. [PMID: 31697553 DOI: 10.1103/physrevlett.123.133902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Indexed: 06/10/2023]
Abstract
We introduce a new class of stable light bullets that form in twisted waveguide arrays pumped with ultrashort pulses, where twisting offers a powerful knob to tune the properties of localized states. We find that, above a critical twist, three-dimensional wave packets are unambiguously stabilized, with no minimum energy threshold. As a consequence, when the higher-order perturbations that accompany ultrashort pulse propagation are at play, the bullets dynamically adjust and sweep along stable branches. Therefore, they are predicted to feature an unprecedented experimental robustness.
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Affiliation(s)
- Carles Milián
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- Institut Universitari de Matemàtica Pura i Aplicada, Universitat Politècnica de València, 46022 (València), Spain
| | - Yaroslav V Kartashov
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- Institute of Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow, 108840, Russia
| | - Lluis Torner
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
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Ren X, Altmann Y, Tobin R, Mccarthy A, Mclaughlin S, Buller GS. Wavelength-time coding for multispectral 3D imaging using single-photon LiDAR. OPTICS EXPRESS 2018; 26:30146-30161. [PMID: 30469893 DOI: 10.1364/oe.26.030146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 10/08/2018] [Indexed: 06/09/2023]
Abstract
Single-photon multispectral light detection and ranging (LiDAR) approaches have emerged as a route to color reconstruction and enhanced target identification in photon-starved imaging scenarios. In this paper, we present a three-dimensional imaging system based on a time-of-flight approach which is capable of simultaneous multispectral measurements using only one single-photon detector. Unlike other techniques, this approach does not require a wavelength router in the receiver channel. By observing multiple wavelengths at each spatial location, or per pixel (four discrete visible wavelengths are used in this work), we can obtain a single waveform with wavelength-to-time mapped peaks. The time-mapped peaks are created by the known chromatic group delay dispersion in the laser source's optical fiber, resulting in temporal separations between these peaks being in the region of 200 to 1000 ps, in this case. A multispectral single waveform algorithm was proposed to fit these multiple peaked LiDAR waveforms, and then reconstruct the color (spectral response) and depth profiles for the entire image. To the best of our knowledge, this is the first dedicated computational method operating in the photon-starved regime capable of discriminating multiple peaks associated with different wavelengths in a single pixel waveform and reconstructing spectral responses and depth.
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Mukherjee S, Chandrasekharan HK, Öhberg P, Goldman N, Thomson RR. State-recycling and time-resolved imaging in topological photonic lattices. Nat Commun 2018; 9:4209. [PMID: 30310062 PMCID: PMC6181942 DOI: 10.1038/s41467-018-06723-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/19/2018] [Indexed: 11/13/2022] Open
Abstract
Photonic lattices—arrays of optical waveguides—are powerful platforms for simulating a range of phenomena, including topological phases. While probing dynamics is possible in these systems, by reinterpreting the propagation direction as time, accessing long timescales constitutes a severe experimental challenge. Here, we overcome this limitation by placing the photonic lattice in a cavity, which allows the optical state to evolve through the lattice multiple times. The accompanying detection method, which exploits a multi-pixel single-photon detector array, offers quasi-real time-resolved measurements after each round trip. We apply the state-recycling scheme to intriguing photonic lattices emulating Dirac fermions and Floquet topological phases. We also realise a synthetic pulsed electric field, which can be used to drive transport within photonic lattices. This work opens an exciting route towards the detection of long timescale effects in engineered photonic lattices and the realisation of hybrid analogue-digital simulators. Topological effects can be emulated using photonic lattices where the length of a waveguide represents time, which is often limited by fabrication constraints. Here, Mukherjee et al. exploit a single-photon detector array enabled state-recycling scheme to increase the accessible time scale.
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Affiliation(s)
- Sebabrata Mukherjee
- Scottish Universities Physics Alliance (SUPA), Institute of Photonics and Quantum Sciences (IPaQS), School of Engineering & Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
| | - Harikumar K Chandrasekharan
- Scottish Universities Physics Alliance (SUPA), Institute of Photonics and Quantum Sciences (IPaQS), School of Engineering & Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Patrik Öhberg
- Scottish Universities Physics Alliance (SUPA), Institute of Photonics and Quantum Sciences (IPaQS), School of Engineering & Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Nathan Goldman
- Center for Nonlinear Phenomena and Complex Systems, Université Libre de Bruxelles, CP 231, Campus Plaine, 1050, Brussels, Belgium.
| | - Robert R Thomson
- Scottish Universities Physics Alliance (SUPA), Institute of Photonics and Quantum Sciences (IPaQS), School of Engineering & Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
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Faccio D, Velten A. A trillion frames per second: the techniques and applications of light-in-flight photography. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:105901. [PMID: 29900876 DOI: 10.1088/1361-6633/aacca1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cameras capable of capturing videos at a trillion frames per second allow to freeze light in motion, a very counterintuitive capability when related to our everyday experience in which light appears to travel instantaneously. By combining this capability with computational imaging techniques, new imaging opportunities emerge such as 3D imaging of scenes that are hidden behind a corner, the study of relativistic distortion effects, imaging through diffusive media and imaging of ultrafast optical processes such as laser ablation, supercontinuum and plasma generation. We provide an overview of the main techniques that have been developed for ultra-high speed photography with a particular focus on 'light-in-flight' imaging, i.e. applications where the key element is the imaging of light itself at frame rates that allow to freeze its motion and therefore extract information that would otherwise be blurred out and lost.
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Affiliation(s)
- Daniele Faccio
- School of Physics & Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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Tanner MG, Choudhary TR, Craven TH, Mills B, Bradley M, Henderson RK, Dhaliwal K, Thomson RR. Ballistic and snake photon imaging for locating optical endomicroscopy fibres. BIOMEDICAL OPTICS EXPRESS 2017; 8:4077-4095. [PMID: 28966848 PMCID: PMC5611924 DOI: 10.1364/boe.8.004077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 07/27/2017] [Accepted: 07/31/2017] [Indexed: 05/10/2023]
Abstract
We demonstrate determination of the location of the distal-end of a fibre-optic device deep in tissue through the imaging of ballistic and snake photons using a time resolved single-photon detector array. The fibre was imaged with centimetre resolution, within clinically relevant settings and models. This technique can overcome the limitations imposed by tissue scattering in optically determining the in vivo location of fibre-optic medical instruments.
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Affiliation(s)
- M. G. Tanner
- Scottish Universities Physics Alliance (SUPA), Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
- EPSRC IRC Hub, MRC Centre for Inflammation Research, Queen’s Medical Research Centre, University of Edinburgh, Edinburgh UK
| | - T. R. Choudhary
- EPSRC IRC Hub, MRC Centre for Inflammation Research, Queen’s Medical Research Centre, University of Edinburgh, Edinburgh UK
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - T. H. Craven
- EPSRC IRC Hub, MRC Centre for Inflammation Research, Queen’s Medical Research Centre, University of Edinburgh, Edinburgh UK
| | - B. Mills
- EPSRC IRC Hub, MRC Centre for Inflammation Research, Queen’s Medical Research Centre, University of Edinburgh, Edinburgh UK
| | - M. Bradley
- EPSRC IRC Hub, MRC Centre for Inflammation Research, Queen’s Medical Research Centre, University of Edinburgh, Edinburgh UK
- School of Chemistry, University of Edinburgh, Edinburgh, UK
| | - R. K. Henderson
- Institute for Integrated Micro and Nano Systems, School of Engineering, University of Edinburgh, Edinburgh EH9 3FF, UK
| | - K. Dhaliwal
- EPSRC IRC Hub, MRC Centre for Inflammation Research, Queen’s Medical Research Centre, University of Edinburgh, Edinburgh UK
| | - R. R. Thomson
- Scottish Universities Physics Alliance (SUPA), Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
- EPSRC IRC Hub, MRC Centre for Inflammation Research, Queen’s Medical Research Centre, University of Edinburgh, Edinburgh UK
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Leon-Saval SG, Betters CH, Salazar-Gil JR, Min SS, Gris-Sanchez I, Birks TA, Lawrence J, Haynes R, Haynes D, Roth M, Veilleux S, Bland-Hawthorn J. Divide and conquer: an efficient solution to highly multimoded photonic lanterns from multicore fibres. OPTICS EXPRESS 2017; 25:17530-17540. [PMID: 28789244 DOI: 10.1364/oe.25.017530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 07/07/2017] [Indexed: 06/07/2023]
Abstract
Photonic lanterns typically allow for single-mode action in a multimode fibre. Since their invention over a decade ago for applications in astrophotonics, they have found important uses in diverse fields of applied science. To date, large aperture highly-mulitmoded to single-mode lanterns have been difficult as fabrication techniques are not practical for mass replication. Here as a proof of concept, we demonstrate three different devices based on multicore fibre photonic lanterns with: 100µm core diameters; NAs = 0.16 and 0.15; and requiring 259 single-mode core system, specifically 7 multicore fibres each with 37 cores, instead of 259 individual single-mode fibres. The average insertion loss excluding coupling efficiencies is only 0.4dB (>91% transmission). This concept has numerous advantages, in particular, (i) it is a direct scaleable solution, (ii) eases imprinting of photonic functions, e.g. fibre Bragg gratings; and (iii) new approach for large-area optical fibre slicers for future large-aperture telescopes.
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